Impact of social relationships on Alzheimer’s memory impairment: mechanistic studies

Abstract

Alzheimer’s disease (AD) is characterized by progressive memory and neuronal loss culminating in cognitive impairment that not only affects a person’s living ability but also becomes a society’s as well as a family’s economic burden. AD is the most common form of dementia in older persons. It is expected that the number of people with AD dementia will increase dramatically in the next 30 years, projecting to 75 million in 2030 and 131.5 million in 2050 worldwide. So far, no sufficient evidence is available to support that any medicine is able to prevent or reverse the progression of the disease. Early studies have shown that social environment, particularly social relationships, can affect one’s behavior and mental health. A study analyzing the correlation between loneliness and risk of developing AD revealed that lonely persons had higher risk of AD compared with persons who were not lonely. On the other hand, it has been reported that we can prevent cognitive decline and delay the onset of AD if we keep mentally active and frequently participate in social activities. In this review, we focus on the impact of social behaviors on the progression of cognitive deficit in animal models of AD with a particular emphasis on a mechanistic scheme that explains how social isolation exacerbates cognitive impairment and how social interaction with conspecifics rescues AD patients’ memory deficit.

Social Isolation Induces Rac1-Dependent Forgetting of Social Memory

“…Social isolation has been shown to be associated with the progression of cognitive deficits, such as in Alzheimer's disease (Donovan et al, 2016), in human and animal models (Hsiao et al, 2018). Thus, the current study may shed light on treatments targeting Rac1 for Alzheimer's disease.…”

Age-related hearing loss and cognitive decline — The potential mechanisms linking the two

“…1C). It has been reported that one can prevent cognitive decline and delay the onset of dementia by maintaining strong social connections [71,72]. Hsiao et al reviewed the impact of social behaviors on the progression of cognitive deficit in animal models of AD and described a mechanistic scheme that explains how social isolation exacerbates cognitive impairment and how social interaction with conspecifics rescues AD-related memory deficits.…”

Effect of 9 weeks continuous vs. interval aerobic training on plasma BDNF levels, aerobic fitness, cognitive capacity and quality of life among seniors with mild to moderate Alzheimer’s disease: a randomized controlled trial

“…Other participants were then considered as nonresponders. This was considered in the three study groups because BDNF level is influenced both by physical activity and social interactions [55,56].…”